text: # Copyright 2014-2015 Canonical Limited.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #  http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from collections import OrderedDict
  import os
  import platform
  import re
  import six
  import time
  import subprocess
  from tempfile import NamedTemporaryFile
  
  from charmhelpers.core.host import (
      lsb_release
  )
  from charmhelpers.core.hookenv import (
      log,
      DEBUG,
  )
  from charmhelpers.fetch import SourceConfigError, GPGKeyError
  
  PROPOSED_POCKET = (
      "# Proposed\n"
      "deb http://archive.ubuntu.com/ubuntu {}-proposed main universe "
      "multiverse restricted\n")
  PROPOSED_PORTS_POCKET = (
      "# Proposed\n"
      "deb http://ports.ubuntu.com/ubuntu-ports {}-proposed main universe "
      "multiverse restricted\n")
  # Only supports 64bit and ppc64 at the moment.
  ARCH_TO_PROPOSED_POCKET = {
      'x86_64': PROPOSED_POCKET,
      'ppc64le': PROPOSED_PORTS_POCKET,
      'aarch64': PROPOSED_PORTS_POCKET,
  }
  CLOUD_ARCHIVE_URL = "http://ubuntu-cloud.archive.canonical.com/ubuntu"
  CLOUD_ARCHIVE_KEY_ID = '5EDB1B62EC4926EA'
  CLOUD_ARCHIVE = """# Ubuntu Cloud Archive
  deb http://ubuntu-cloud.archive.canonical.com/ubuntu {} main
  """
  CLOUD_ARCHIVE_POCKETS = {
      # Folsom
      'folsom': 'precise-updates/folsom',
      'folsom/updates': 'precise-updates/folsom',
      'precise-folsom': 'precise-updates/folsom',
      'precise-folsom/updates': 'precise-updates/folsom',
      'precise-updates/folsom': 'precise-updates/folsom',
      'folsom/proposed': 'precise-proposed/folsom',
      'precise-folsom/proposed': 'precise-proposed/folsom',
      'precise-proposed/folsom': 'precise-proposed/folsom',
      # Grizzly
      'grizzly': 'precise-updates/grizzly',
      'grizzly/updates': 'precise-updates/grizzly',
      'precise-grizzly': 'precise-updates/grizzly',
      'precise-grizzly/updates': 'precise-updates/grizzly',
      'precise-updates/grizzly': 'precise-updates/grizzly',
      'grizzly/proposed': 'precise-proposed/grizzly',
      'precise-grizzly/proposed': 'precise-proposed/grizzly',
      'precise-proposed/grizzly': 'precise-proposed/grizzly',
      # Havana
      'havana': 'precise-updates/havana',
      'havana/updates': 'precise-updates/havana',
      'precise-havana': 'precise-updates/havana',
      'precise-havana/updates': 'precise-updates/havana',
      'precise-updates/havana': 'precise-updates/havana',
      'havana/proposed': 'precise-proposed/havana',
      'precise-havana/proposed': 'precise-proposed/havana',
      'precise-proposed/havana': 'precise-proposed/havana',
      # Icehouse
      'icehouse': 'precise-updates/icehouse',
      'icehouse/updates': 'precise-updates/icehouse',
      'precise-icehouse': 'precise-updates/icehouse',
      'precise-icehouse/updates': 'precise-updates/icehouse',
      'precise-updates/icehouse': 'precise-updates/icehouse',
      'icehouse/proposed': 'precise-proposed/icehouse',
      'precise-icehouse/proposed': 'precise-proposed/icehouse',
      'precise-proposed/icehouse': 'precise-proposed/icehouse',
      # Juno
      'juno': 'trusty-updates/juno',
      'juno/updates': 'trusty-updates/juno',
      'trusty-juno': 'trusty-updates/juno',
      'trusty-juno/updates': 'trusty-updates/juno',
      'trusty-updates/juno': 'trusty-updates/juno',
      'juno/proposed': 'trusty-proposed/juno',
      'trusty-juno/proposed': 'trusty-proposed/juno',
      'trusty-proposed/juno': 'trusty-proposed/juno',
      # Kilo
      'kilo': 'trusty-updates/kilo',
      'kilo/updates': 'trusty-updates/kilo',
      'trusty-kilo': 'trusty-updates/kilo',
      'trusty-kilo/updates': 'trusty-updates/kilo',
      'trusty-updates/kilo': 'trusty-updates/kilo',
      'kilo/proposed': 'trusty-proposed/kilo',
      'trusty-kilo/proposed': 'trusty-proposed/kilo',
      'trusty-proposed/kilo': 'trusty-proposed/kilo',
      # Liberty
      'liberty': 'trusty-updates/liberty',
      'liberty/updates': 'trusty-updates/liberty',
      'trusty-liberty': 'trusty-updates/liberty',
      'trusty-liberty/updates': 'trusty-updates/liberty',
      'trusty-updates/liberty': 'trusty-updates/liberty',
      'liberty/proposed': 'trusty-proposed/liberty',
      'trusty-liberty/proposed': 'trusty-proposed/liberty',
      'trusty-proposed/liberty': 'trusty-proposed/liberty',
      # Mitaka
      'mitaka': 'trusty-updates/mitaka',
      'mitaka/updates': 'trusty-updates/mitaka',
      'trusty-mitaka': 'trusty-updates/mitaka',
      'trusty-mitaka/updates': 'trusty-updates/mitaka',
      'trusty-updates/mitaka': 'trusty-updates/mitaka',
      'mitaka/proposed': 'trusty-proposed/mitaka',
      'trusty-mitaka/proposed': 'trusty-proposed/mitaka',
      'trusty-proposed/mitaka': 'trusty-proposed/mitaka',
      # Newton
      'newton': 'xenial-updates/newton',
      'newton/updates': 'xenial-updates/newton',
      'xenial-newton': 'xenial-updates/newton',
      'xenial-newton/updates': 'xenial-updates/newton',
      'xenial-updates/newton': 'xenial-updates/newton',
      'newton/proposed': 'xenial-proposed/newton',
      'xenial-newton/proposed': 'xenial-proposed/newton',
      'xenial-proposed/newton': 'xenial-proposed/newton',
      # Ocata
      'ocata': 'xenial-updates/ocata',
      'ocata/updates': 'xenial-updates/ocata',
      'xenial-ocata': 'xenial-updates/ocata',
      'xenial-ocata/updates': 'xenial-updates/ocata',
      'xenial-updates/ocata': 'xenial-updates/ocata',
      'ocata/proposed': 'xenial-proposed/ocata',
      'xenial-ocata/proposed': 'xenial-proposed/ocata',
      'xenial-ocata/newton': 'xenial-proposed/ocata',
      # Pike
      'pike': 'xenial-updates/pike',
      'xenial-pike': 'xenial-updates/pike',
      'xenial-pike/updates': 'xenial-updates/pike',
      'xenial-updates/pike': 'xenial-updates/pike',
      'pike/proposed': 'xenial-proposed/pike',
      'xenial-pike/proposed': 'xenial-proposed/pike',
      'xenial-pike/newton': 'xenial-proposed/pike',
      # Queens
      'queens': 'xenial-updates/queens',
      'xenial-queens': 'xenial-updates/queens',
      'xenial-queens/updates': 'xenial-updates/queens',
      'xenial-updates/queens': 'xenial-updates/queens',
      'queens/proposed': 'xenial-proposed/queens',
      'xenial-queens/proposed': 'xenial-proposed/queens',
      'xenial-queens/newton': 'xenial-proposed/queens',
  }
  
  
  APT_NO_LOCK = 100  # The return code for "couldn't acquire lock" in APT.
  CMD_RETRY_DELAY = 10  # Wait 10 seconds between command retries.
  CMD_RETRY_COUNT = 30  # Retry a failing fatal command X times.
  
  
  def filter_installed_packages(packages):
      """Return a list of packages that require installation."""
      cache = apt_cache()
      _pkgs = []
      for package in packages:
          try:
              p = cache[package]
              p.current_ver or _pkgs.append(package)
          except KeyError:
              log('Package {} has no installation candidate.'.format(package),
                  level='WARNING')
              _pkgs.append(package)
      return _pkgs
  
  
  def apt_cache(in_memory=True, progress=None):
      """Build and return an apt cache."""
      from apt import apt_pkg
      apt_pkg.init()
      if in_memory:
          apt_pkg.config.set("Dir::Cache::pkgcache", "")
          apt_pkg.config.set("Dir::Cache::srcpkgcache", "")
      return apt_pkg.Cache(progress)
  
  
  def apt_install(packages, options=None, fatal=False):
      """Install one or more packages."""
      if options is None:
          options = ['--option=Dpkg::Options::=--force-confold']
  
      cmd = ['apt-get', '--assume-yes']
      cmd.extend(options)
      cmd.append('install')
      if isinstance(packages, six.string_types):
          cmd.append(packages)
      else:
          cmd.extend(packages)
      log("Installing {} with options: {}".format(packages,
                                                  options))
      _run_apt_command(cmd, fatal)
  
  
  def apt_upgrade(options=None, fatal=False, dist=False):
      """Upgrade all packages."""
      if options is None:
          options = ['--option=Dpkg::Options::=--force-confold']
  
      cmd = ['apt-get', '--assume-yes']
      cmd.extend(options)
      if dist:
          cmd.append('dist-upgrade')
      else:
          cmd.append('upgrade')
      log("Upgrading with options: {}".format(options))
      _run_apt_command(cmd, fatal)
  
  
  def apt_update(fatal=False):
      """Update local apt cache."""
      cmd = ['apt-get', 'update']
      _run_apt_command(cmd, fatal)
  
  
  def apt_purge(packages, fatal=False):
      """Purge one or more packages."""
      cmd = ['apt-get', '--assume-yes', 'purge']
      if isinstance(packages, six.string_types):
          cmd.append(packages)
      else:
          cmd.extend(packages)
      log("Purging {}".format(packages))
      _run_apt_command(cmd, fatal)
  
  
  def apt_mark(packages, mark, fatal=False):
      """Flag one or more packages using apt-mark."""
      log("Marking {} as {}".format(packages, mark))
      cmd = ['apt-mark', mark]
      if isinstance(packages, six.string_types):
          cmd.append(packages)
      else:
          cmd.extend(packages)
  
      if fatal:
          subprocess.check_call(cmd, universal_newlines=True)
      else:
          subprocess.call(cmd, universal_newlines=True)
  
  
  def apt_hold(packages, fatal=False):
      return apt_mark(packages, 'hold', fatal=fatal)
  
  
  def apt_unhold(packages, fatal=False):
      return apt_mark(packages, 'unhold', fatal=fatal)
  
  
  def import_key(keyid):
      """Import a key in either ASCII Armor or Radix64 format.
  
      `keyid` is either the keyid to fetch from a PGP server, or
      the key in ASCII armor foramt.
  
      :param keyid: String of key (or key id).
      :raises: GPGKeyError if the key could not be imported
      """
      key = keyid.strip()
      if (key.startswith('-----BEGIN PGP PUBLIC KEY BLOCK-----') and
              key.endswith('-----END PGP PUBLIC KEY BLOCK-----')):
          log("PGP key found (looks like ASCII Armor format)", level=DEBUG)
          log("Importing ASCII Armor PGP key", level=DEBUG)
          with NamedTemporaryFile() as keyfile:
              with open(keyfile.name, 'w') as fd:
                  fd.write(key)
                  fd.write("\n")
              cmd = ['apt-key', 'add', keyfile.name]
              try:
                  subprocess.check_call(cmd)
              except subprocess.CalledProcessError:
                  error = "Error importing PGP key '{}'".format(key)
                  log(error)
                  raise GPGKeyError(error)
      else:
          log("PGP key found (looks like Radix64 format)", level=DEBUG)
          log("Importing PGP key from keyserver", level=DEBUG)
          cmd = ['apt-key', 'adv', '--keyserver',
                 'hkp://keyserver.ubuntu.com:80', '--recv-keys', key]
          try:
              subprocess.check_call(cmd)
          except subprocess.CalledProcessError:
              error = "Error importing PGP key '{}'".format(key)
              log(error)
              raise GPGKeyError(error)
  
  
  def add_source(source, key=None, fail_invalid=False):
      """Add a package source to this system.
  
      @param source: a URL or sources.list entry, as supported by
      add-apt-repository(1). Examples::
  
          ppa:charmers/example
          deb https://stub:key@private.example.com/ubuntu trusty main
  
      In addition:
          'proposed:' may be used to enable the standard 'proposed'
          pocket for the release.
          'cloud:' may be used to activate official cloud archive pockets,
          such as 'cloud:icehouse'
          'distro' may be used as a noop
  
      Full list of source specifications supported by the function are:
  
      'distro': A NOP; i.e. it has no effect.
      'proposed': the proposed deb spec [2] is wrtten to
        /etc/apt/sources.list/proposed
      'distro-proposed': adds <version>-proposed to the debs [2]
      'ppa:<ppa-name>': add-apt-repository --yes <ppa_name>
      'deb <deb-spec>': add-apt-repository --yes deb <deb-spec>
      'http://....': add-apt-repository --yes http://...
      'cloud-archive:<spec>': add-apt-repository -yes cloud-archive:<spec>
      'cloud:<release>[-staging]': specify a Cloud Archive pocket <release> with
        optional staging version.  If staging is used then the staging PPA [2]
        with be used.  If staging is NOT used then the cloud archive [3] will be
        added, and the 'ubuntu-cloud-keyring' package will be added for the
        current distro.
  
      Otherwise the source is not recognised and this is logged to the juju log.
      However, no error is raised, unless sys_error_on_exit is True.
  
      [1] deb http://ubuntu-cloud.archive.canonical.com/ubuntu {} main
          where {} is replaced with the derived pocket name.
      [2] deb http://archive.ubuntu.com/ubuntu {}-proposed \
          main universe multiverse restricted
          where {} is replaced with the lsb_release codename (e.g. xenial)
      [3] deb http://ubuntu-cloud.archive.canonical.com/ubuntu <pocket>
          to /etc/apt/sources.list.d/cloud-archive-list
  
      @param key: A key to be added to the system's APT keyring and used
      to verify the signatures on packages. Ideally, this should be an
      ASCII format GPG public key including the block headers. A GPG key
      id may also be used, but be aware that only insecure protocols are
      available to retrieve the actual public key from a public keyserver
      placing your Juju environment at risk. ppa and cloud archive keys
      are securely added automtically, so sould not be provided.
  
      @param fail_invalid: (boolean) if True, then the function raises a
      SourceConfigError is there is no matching installation source.
  
      @raises SourceConfigError() if for cloud:<pocket>, the <pocket> is not a
      valid pocket in CLOUD_ARCHIVE_POCKETS
      """
      _mapping = OrderedDict([
          (r"^distro$", lambda: None),  # This is a NOP
          (r"^(?:proposed|distro-proposed)$", _add_proposed),
          (r"^cloud-archive:(.*)$", _add_apt_repository),
          (r"^((?:deb |http:|https:|ppa:).*)$", _add_apt_repository),
          (r"^cloud:(.*)-(.*)\/staging$", _add_cloud_staging),
          (r"^cloud:(.*)-(.*)$", _add_cloud_distro_check),
          (r"^cloud:(.*)$", _add_cloud_pocket),
      ])
      if source is None:
          source = ''
      for r, fn in six.iteritems(_mapping):
          m = re.match(r, source)
          if m:
              # call the assoicated function with the captured groups
              # raises SourceConfigError on error.
              fn(*m.groups())
              if key:
                  try:
                      import_key(key)
                  except GPGKeyError as e:
                      raise SourceConfigError(str(e))
              break
      else:
          # nothing matched.  log an error and maybe sys.exit
          err = "Unknown source: {!r}".format(source)
          log(err)
          if fail_invalid:
              raise SourceConfigError(err)
  
  
  def _add_proposed():
      """Add the PROPOSED_POCKET as /etc/apt/source.list.d/proposed.list
  
      Uses lsb_release()['DISTRIB_CODENAME'] to determine the correct staza for
      the deb line.
  
      For intel architecutres PROPOSED_POCKET is used for the release, but for
      other architectures PROPOSED_PORTS_POCKET is used for the release.
      """
      release = lsb_release()['DISTRIB_CODENAME']
      arch = platform.machine()
      if arch not in six.iterkeys(ARCH_TO_PROPOSED_POCKET):
          raise SourceConfigError("Arch {} not supported for (distro-)proposed"
                                  .format(arch))
      with open('/etc/apt/sources.list.d/proposed.list', 'w') as apt:
          apt.write(ARCH_TO_PROPOSED_POCKET[arch].format(release))
  
  
  def _add_apt_repository(spec):
      """Add the spec using add_apt_repository
  
      :param spec: the parameter to pass to add_apt_repository
      """
      _run_with_retries(['add-apt-repository', '--yes', spec])
  
  
  def _add_cloud_pocket(pocket):
      """Add a cloud pocket as /etc/apt/sources.d/cloud-archive.list
  
      Note that this overwrites the existing file if there is one.
  
      This function also converts the simple pocket in to the actual pocket using
      the CLOUD_ARCHIVE_POCKETS mapping.
  
      :param pocket: string representing the pocket to add a deb spec for.
      :raises: SourceConfigError if the cloud pocket doesn't exist or the
          requested release doesn't match the current distro version.
      """
      apt_install(filter_installed_packages(['ubuntu-cloud-keyring']),
                  fatal=True)
      if pocket not in CLOUD_ARCHIVE_POCKETS:
          raise SourceConfigError(
              'Unsupported cloud: source option %s' %
              pocket)
      actual_pocket = CLOUD_ARCHIVE_POCKETS[pocket]
      with open('/etc/apt/sources.list.d/cloud-archive.list', 'w') as apt:
          apt.write(CLOUD_ARCHIVE.format(actual_pocket))
  
  
  def _add_cloud_staging(cloud_archive_release, openstack_release):
      """Add the cloud staging repository which is in
      ppa:ubuntu-cloud-archive/<openstack_release>-staging
  
      This function checks that the cloud_archive_release matches the current
      codename for the distro that charm is being installed on.
  
      :param cloud_archive_release: string, codename for the release.
      :param openstack_release: String, codename for the openstack release.
      :raises: SourceConfigError if the cloud_archive_release doesn't match the
          current version of the os.
      """
      _verify_is_ubuntu_rel(cloud_archive_release, openstack_release)
      ppa = 'ppa:ubuntu-cloud-archive/{}-staging'.format(openstack_release)
      cmd = 'add-apt-repository -y {}'.format(ppa)
      _run_with_retries(cmd.split(' '))
  
  
  def _add_cloud_distro_check(cloud_archive_release, openstack_release):
      """Add the cloud pocket, but also check the cloud_archive_release against
      the current distro, and use the openstack_release as the full lookup.
  
      This just calls _add_cloud_pocket() with the openstack_release as pocket
      to get the correct cloud-archive.list for dpkg to work with.
  
      :param cloud_archive_release:String, codename for the distro release.
      :param openstack_release: String, spec for the release to look up in the
          CLOUD_ARCHIVE_POCKETS
      :raises: SourceConfigError if this is the wrong distro, or the pocket spec
          doesn't exist.
      """
      _verify_is_ubuntu_rel(cloud_archive_release, openstack_release)
      _add_cloud_pocket("{}-{}".format(cloud_archive_release, openstack_release))
  
  
  def _verify_is_ubuntu_rel(release, os_release):
      """Verify that the release is in the same as the current ubuntu release.
  
      :param release: String, lowercase for the release.
      :param os_release: String, the os_release being asked for
      :raises: SourceConfigError if the release is not the same as the ubuntu
          release.
      """
      ubuntu_rel = lsb_release()['DISTRIB_CODENAME']
      if release != ubuntu_rel:
          raise SourceConfigError(
              'Invalid Cloud Archive release specified: {}-{} on this Ubuntu'
              'version ({})'.format(release, os_release, ubuntu_rel))
  
  
  def _run_with_retries(cmd, max_retries=CMD_RETRY_COUNT, retry_exitcodes=(1,),
                        retry_message="", cmd_env=None):
      """Run a command and retry until success or max_retries is reached.
  
      :param: cmd: str: The apt command to run.
      :param: max_retries: int: The number of retries to attempt on a fatal
          command. Defaults to CMD_RETRY_COUNT.
      :param: retry_exitcodes: tuple: Optional additional exit codes to retry.
          Defaults to retry on exit code 1.
      :param: retry_message: str: Optional log prefix emitted during retries.
      :param: cmd_env: dict: Environment variables to add to the command run.
      """
  
      env = None
      kwargs = {}
      if cmd_env:
          env = os.environ.copy()
          env.update(cmd_env)
          kwargs['env'] = env
  
      if not retry_message:
          retry_message = "Failed executing '{}'".format(" ".join(cmd))
      retry_message += ". Will retry in {} seconds".format(CMD_RETRY_DELAY)
  
      retry_count = 0
      result = None
  
      retry_results = (None,) + retry_exitcodes
      while result in retry_results:
          try:
              # result = subprocess.check_call(cmd, env=env)
              result = subprocess.check_call(cmd, **kwargs)
          except subprocess.CalledProcessError as e:
              retry_count = retry_count + 1
              if retry_count > max_retries:
                  raise
              result = e.returncode
              log(retry_message)
              time.sleep(CMD_RETRY_DELAY)
  
  
  def _run_apt_command(cmd, fatal=False):
      """Run an apt command with optional retries.
  
      :param: cmd: str: The apt command to run.
      :param: fatal: bool: Whether the command's output should be checked and
          retried.
      """
      # Provide DEBIAN_FRONTEND=noninteractive if not present in the environment.
      cmd_env = {
          'DEBIAN_FRONTEND': os.environ.get('DEBIAN_FRONTEND', 'noninteractive')}
  
      if fatal:
          _run_with_retries(
              cmd, cmd_env=cmd_env, retry_exitcodes=(1, APT_NO_LOCK,),
              retry_message="Couldn't acquire DPKG lock")
      else:
          env = os.environ.copy()
          env.update(cmd_env)
          subprocess.call(cmd, env=env)
  
  
  def get_upstream_version(package):
      """Determine upstream version based on installed package
  
      @returns None (if not installed) or the upstream version
      """
      import apt_pkg
      cache = apt_cache()
      try:
          pkg = cache[package]
      except:
          # the package is unknown to the current apt cache.
          return None
  
      if not pkg.current_ver:
          # package is known, but no version is currently installed.
          return None
  
      return apt_pkg.upstream_version(pkg.current_ver.ver_str)
  